The handle of a tennis racket has, at one end, a plastic cap which is an enlarged end piece to support the hand and to prevent the tennis racket from slipping forward. The other end of the handle leads to the head portion of the frame. To enable the hand to hold firmly onto the handle, the prior art always has a soft grip strip wrapped over the shaft along the whole length of the handle. The grip strip, or called grip, in the earlier time, is made of leather, cut into long strip and wrapped spirally around the shaft to make the handle. In recent times, synthetic sponge grips, are also used with increasing popularity. The merit of synthetic sponge grip is that it has better cushioning effect and better moisture absorption and frictional quality than leather.
When the hand is sweaty, the moisture acts as a kind of lubricant, the grip becomes slippery. There are two directions along which the handle may slip: one is along the longitudinal axis of the handle and the other is the rotational direction. The rotational direction slippery is more serious because the diameter of the handle of a tennis racket is small and there is not much moment arm for leverage. An off center-line shot by the ball can easily twist the racket out of control if the grip is slippery.